Current conditions at selected sites based on the most recent data from on-site automated recording equipment.
Measurements are commonly recorded at a fixed interval of 15- to 60-minutes and transmitted to the USGS every hour.
Values may include "Approved" (quality-assured data that may be published) and/or more recent "Provisional" data
(of unverified accuracy and subject to revision). Most current data are provisional.

The same data accessed by the Current Conditions link above but including both active and discontinued sites
with data for any part of the period October 1, 2007, through the present. Values may include "Approved"
(quality-assured data that may be published) and/or more recent "Provisional" data
(of unverified accuracy and subject to revision).

Summary of all data for each day for the period of record
and may represent the daily mean, median, maximum, minimum, and/or other derived value.
Values may include "Approved" (quality-assured data that may be published) and/or more recent "Provisional" data
(of unverified accuracy and subject to revision).
Example.

Statistics are computed from approved daily mean data at each site.
These links provide summaries of approved historical daily values for daily,
monthly, and annual (water year or calendar year) time periods.

Manual measurements of streamflow and gage height. These measurements
are used to supplement and (or) verify the accuracy of the automatically recorded observations, as well
as to compute streamflow based on gage height.

Introduction

Nationally, USGS surface-water data includes more
than 850,000 station years of time-series data that describe stream
levels, streamflow (discharge), reservoir and lake levels,
surface-water quality, and rainfall. The data are collected by
automatic recorders and manual measurements at field installations across
the Nation.

Data are collected by field personnel or relayed
through telephones or satellites to offices where it is stored and
processed. The data relayed through the Geostationary Operational
Environmental Satellite (GOES) system are processed automatically in
near real time, and in many cases, real-time
data are available online within minutes.

Once a complete day of readings are received from a
site, daily summary data are generated and stored in the data base.
Recent provisional daily data are updated on
the web once a day when the computation is completed.

Annually, the USGS finalizes and publishes the daily
data in a series of water-data reports. Daily
streamflow data and peak data are
updated annually following publication of the reports.